efriedma-quic wrote: > > I'm skeptical this actually makes sense in its current form. LLVM > > internally has a thing it calls a basic block, but what exactly counts is, > > to some extent, machine-specific, and can change from version to version. > > I guess regardless of whether we call it BB alignment or label alignment, the > concept is already supported on the frontend side for loops. My idea was that > we could lift it to the function level, forcing all the function "labels" be > aligned on a certain boundary.
Aligning the targets of branches is a different thing from what you've implemented. There are basic blocks which are not branch targets, and there are branch targets which are not at the beginning of a basic block. (Branch targets that aren't at the beginning of a basic block are rare on most targets, but it doesn't seem like something we should completely ignore.) "Loop alignment" is specifically a request to override the normal compiler heuristics for aligning the loop header i.e. the target of the loop backedges. This is best-effort; a "loop" in C code might not lower to something that actually has a header we can align. "-malign-branch-boundary" specifically inserts padding so branch instructions don't cross a 32-byte boundary; it isn't trying to align anything. https://github.com/llvm/llvm-project/pull/80765 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
